Audi 100 CD 2226cc Auto leggy box stuffed

Anyone know where I can get hold of a replacement auto box mine has blown
2nd time after 250k miles. I have been quoted upwards of £1200 as they think
the bearings have gone in the diff as well to get the oil contamination in
the box and break the seal between them though until it comes out on the
bench who knows it might be just the seal but there is quite a lot of play
when you engage gears and all of the CV joints both sides have been replaced
50k miles before so there shouldn't be any play at all except in the diff I
suppose. My fault really I regularly use the 130mph+ where I can for 400
hundred plus mile runs though I did check the levels all the time must have
just been ready for a good overhaul at this mileage as opposed to just doing
the gearbox plates et al.